1. Field of Invention
The present invention relates to a seat such as an automotive seat, and in particular to the seat having a trim cover assembly on which plural decorative stitches are formed.
2. Description of Prior Art
All the hitherto known automotive seats include such a seat that comprises a foam cushion body molded in a foaming process using a polyurethane material, and a trim cover assembly covering the foam cushion body. Recent years witness that forming plural decorative stitched seams on the trim cover assembly has been practiced increasingly. It is thought advisable to use a multiple-needle sewing machine to create such plural stitches in a parallel fashion at one time so as to meat a required mass-production of this kind of seat. (See, for example, the Japanese Laid-Open Pat. Pub. No. 64-34394.)
However, this parallel stitching has been found difficult for application to such new mode of seat cushion with a protruded portion which is sloped or inclined in its longitudinal direction, because, if a unitary sheet of trim cover assembly is affixed over the uneven upper surface of seat cushion, the plural stitched seams on the trim cover assembly are twisted or deformed into an objectionable non-rectilinear or non-parallel pattern.
Possible solution may be to prepare a plurality of separate sections having parallel stitches thereon by use of multiple-needle sewing machine and then sew them together to form a suitable trim cover assembly that lies along the upper surfaces and the protruded portion on the cushion body. According to this technique, plural decorative stitched seams (41, 42, 43 . . . ) are formed in parallel with one another upon the respective three separate sheets of trim cover assembly (1) and sewn together at the joint lines (101) as shown on FIG. 1(A). With further reference to FIGS. 1(A) and 1(B), each of the three sheets should be prepared as best shown in FIG. 1(B): A central section (11-1), a left-side lateral section (11-2) and a right-side lateral section (11-3). Then, they are each formed with their own parallel stitch patterns (41, 42, 43) by means of multiple-needle sewing machine (see at (M) in FIG. 4). Thereafter, considering the fact that the parallel stitches in the two lateral sections (11-2) (11-3) must be inclined in conformity with the inclination angle of the sloped, protruded portion of the cushion body, some hand operation steps are carried on to cut the respective lateral ends of lateral sections (11-2) (11-3) at such inclination angle as indicated by (100) in FIG. 1(B), conforming to that particular inclination angle, and then sew them with the central section (11-1) to obtain such representation of a whole trim cover assembly (1), or strictly stated a representation of a seating surface section of a trim cover assembly (1). As shown in FIG. 1(C), the trim cover assembly (1) is of a three-layer lamination structure including a top surface layer (111), wadding (112) and wadding cover (11 3). Consequently, the trim cover assembly (1) thus formed is affixed over the cushion body, whereupon the two lateral sections (11-2) (11-2) thereof are displaced towards the protruded portion (H). Hence, there is obtained such a trim cover assembly (1).
Nonetheless, this approach involves quite troublesome and intricate steps on the worker's part to put together those separate trim cover sections, and the joint lines (101) poses an objectionable point on the seat, not contributing to improvement on the aesthetic appearance of seat. What is worse, it is impossible to subject a whole unitary sheet of trim cover assembly to stitching at one time by means of ordinary rectilinear-sewing-type multiple-needle sewing machine.